Very basic Null value question

[BlueIshDan]

Public Function ValidString(str) As Boolean
       ValidString = (Len(str + vbNullString) > 0)
End Function

parameter str has value = Null

why is Len(str + vbNullString) returning Null
I've used this method for a while now and I've never had issues with Null until now...

This produceses runtime error 92.

 

[pbaldy]

Have you tried "&" instead of "+"? "+" propagates Nulls, "&" does not.

 

[pr2-eugin]

& is used for concatenation + is used for Null propagation. So,

Null & vbNullString = vbNullString
Null + vbNullString = Null

That is why you get the error.

 

[BlueIshDan]

Omf that's it. I've been working in python and javascript a lot recently lol. I can't believe that slipped my mind! Thank you so much pbaldy and paul

 

[pr2-eugin]

The Paul's are happy to help Good luck !

 

[Brianwarnock]

Oh dear Paul it's a good job col doesn't read the techie stuff, what's with the ' , is your other job a grocer?

Brian